“The arrogance of these men, in particular of Parsons, meant they thought they could get away with what they were doing. They couldn’t have been more wrong.

“As with the other gangs willing to put lives at risk by using highly explosive gas to attack cashpoints in the Avon and Somerset area, the judge has handed out significant sentences which reflect the nature of their crimes and which I hope act as a further deterrent to others.”

Barnes, aged 22, and Joyner, aged 23, of Wroughton Drive in Hartcliffe, pleaded guilty to charges of conspiracy to cause an explosion. They received sentences of five and seven-and-a-half years respectively.

Gwyther, aged 22, of Kenmare Road in Knowle, was found guilty of the same offence by a jury and was jailed for 10 years.

Parsons, aged 27, was jailed for five years at a previous hearing, although he has another 10 years’ worth of sentences for similar crimes in 2015.

Det Ch Insp Iddon said: “Since the start of last year, we have been working closely with the ATM industry to make it harder for criminals to steal money.

“More ATMs across the force area have been fitted with equipment designed to stop these kinds of attacks from happening, including armoured plating, while many also now have forensic water dispersal units installed which spray offenders with an indelible liquid.

“These measures either make the cash cassettes harder to access or make it easier to identify those involved in such attacks and I think they have had a noticeable effect.”